1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2023, SUSE. */
 3
 4#include "vmlinux.h"
 5#include <bpf/bpf_tracing.h>
 6#include "bpf_tracing_net.h"
 7
 8char _license[] SEC("license") = "GPL";
 9
10SEC("fmod_ret/update_socket_protocol")
11int BPF_PROG(mptcpify, int family, int type, int protocol)
12{
13	if ((family == AF_INET || family == AF_INET6) &&
14	    type == SOCK_STREAM &&
15	    (!protocol || protocol == IPPROTO_TCP)) {
16		return IPPROTO_MPTCP;
17	}
18
19	return protocol;
20}